#include <iostream>
#include <fstream>

using namespace std;

ifstream f("fact.in");
ofstream g("fact.out");

int main()
{
    int n,a=0,ac;
    f>>n;
    ac=n;
    while(ac%5==0)
        ac/=5;
    if(ac==1)
    {
        g<<"-1";
        return 0;
    }
    if(n<=0)
        a=1;
    else while(n!=0)
        {
            a+=5;
            ac=a;
            while(ac%5==0)
            {
                ac/=5;
                n--;
            }
            /*if(n<0)
            {
                g<<"-1";
                return 0;
            }*/

        }
    g<<a;
    return 0;
}